Development in the field of teeth whitening has led to the present method of "power bleaching". The method begins with placing a rubber sheet or dam over the patient's teeth and pushing the teeth through the sheet. This protects the soft tissues of the gums from oxidation by peroxides used in bleaching. However, since the rubber sheet stretches and does not custom fit the particular patient's mouth, the peroxide can leak around the rubber sheet and cause substantial discomfort to the patient. Typically, this method can be performed only on the upper or lower set of teeth at one time, not both.
Once the rubber sheet is in place, a peroxide solution is coated on the teeth. Since the bleaching effects of peroxide are slow, the common practice is to apply heat to the peroxide to accelerate the reaction. This is accomplished with the use of a heat lamp or heating iron. Although the heat accelerates the bleaching process, a substantial amount of time is still required so that the entire bleaching process must be performed over several appointments, resulting in inconvenience, time loss, and substantial expense.
The heat lamp activates the peroxide on a plurality of teeth simultaneously but also exposes the patient's face to the heat, which is quite uncomfortable and cannot be endured for a prolonged period. While the heating iron does not expose the patient's face to the same extent as the heat lamp, it takes a much longer time to perform the whitening since it affects only one or two teeth at a time. In addition, prolonged exposure to heat will increase the temperature of the pulp within the tooth. Since the amount of heat commonly used in this type of procedure could kill the pulp and cause tooth loss if exposure is prolonged, continuous exposure must be limited. As a result, 2 to 5 office visits are required before adequate bleaching is attained. From the foregoing it maybe seen that there is still a need for a method of whitening teeth which better protects the soft tissues, shortens the time for the procedure, and reduces the discomfort to the patient.